Nikzad-Rahbar said that "Iranian Oil Ministry has passed the initial hard days of sanction (on its energy sector) thanks to the industrious staff and the special attention given to the oil industry in the country," according to semi-official Mehr news agency.

Directors and workers in oil industry work day and night and employ special ploys to ward off the sanctions and they will leave the enemy disappointed, indicating that the sanctioning agents possess nothing by which to pressure the Iranian oil industry, he was quoted as saying.

On Monday, local media, quoting Iranian Oil Minister Rostam Qasemi, reported that due to the Western sanctions, Iran's oil sales had dropped by 40 percent in the past nine months.

Also, head of Iran's Majlis (parliament) Plan and Budget Commission, Gholam-Reza Kateb, referring to the oil minister's remarks in the parliament, told semi-official ISNA news agency that oil sales in the country have dropped by 40 percent, while gas and oil revenues fell by 45 percent compared to the same period last year.

Iranian officials, including the oil minister, had consistently denied that the Western sanctions had any impact on the country's oil sales or revenues.

Iran for decades has been a large oil provider to the global energy market. Oil exports provide over 70 percent of the Iranian government's revenues. However, according to the International Energy Agency (IEA), the country's oil exports declined from 2.5 million barrels per day in December 2011 to about 1.25 million barrels per day as of December 2012.

Iran is under unilateral Western sanction pressure on its crude oil and natural gas exports. The West has accused Iran of secretly developing nuclear weapons under the guise of its civilian nuclear program, a charge Tehran has consistently denied.